Fluid-pressure brake



March 24, C. C. FARMER FLUID PRESSURE BRAKE Filed NOV. 9, 1929 ,lli

p I u N i v Vl by INVENTOR CLYDEC FARMER BY Q/@d/ ATTOR EY Patented Mar. 24, 1931 or PENNSYLVANIA .rLurD-rnnssnan isn-AXE Appiicarion filed Nef/@mbar a, 192e. semi-no. 405,895.y

Tliis'zinvention relates tok fluid vpressure brakes and has for/its principal object to provide means whereby the engineer may obtain-at will'either a direct release of the "5l brakes in the train or a retained fluid pressure in th-e brake cylinder in releasing the brakes.

In the accompanying drawing, the single figure is a sectional View of a car fluid pressure brake apparatus embodying my invention. v The'equipment shown in the drawing comprises a triple valve device 1, a brake cylinder 2, an auxiliary reservoir 3, a brake pipe 4, and a pressure retaining valve device 5. The triple valve device l may be of the usual construction comprising ay casing 6 having a piston chamber, 7 connected-to'` the brake pipe, 4.a nd containing a piston Sand" having a valve chamber 9 connected to theauxiliary reservoir 3 and containing .a main slide valve l0 and a graduating slide valve 11, adapted to be operated by piston 8. Y

In addition, av release controlling valve device may be associated with the triple valve device and may comprise a iillingpiece 12 containing aldiaphragm 13 having the cham-' ber 14at one side connected through apas- -3'0 sage 15 with the 'auxiliary` reservoir 3. A

springV stopV member 16, subject tothe pressure-of a coil vspring 17, is mounted in cham ber 18, and engages the diaphragm .13..V A valve stem 19', having aV guiding fits-in a` bore 20 of thellling piece 12 and in a bore'of a partition-wall 21 is adapted to operate a slide valve 22 forA controlling communication from f an exhaust passage 23, leading to the seat of slide valve 10,-to valve chamber 24, whichis open to the atmosphere through passage 25. The valve l22is subject to the pressure of a spring 26, which acts'o'n the valve through ay roller 27. j A coil'spring 28 on thestem 19 is interposed between the wall 21 anda collar 29 on the stem and tends to maintain'the valve stein in the. position shown in the drawing.

Also containedy inthe filling piece 12 isY a diaphragm 30, having the chamber 31 at one side :connected to a passage 32, which comfollower 33 engages'the opposite side of the municates with the brake pipe'4b' vA springk diaphragm '30 and"` is subjectl to they pressure of a coil spring 34g" Arpin 35` is provided, having a teat adapted to engage in an annulargroove 36 on the stem'lQ, when the' stem is moved so that the teat is in alineinentfwith the groove. i The pin is provided witha flangewhich is mounted in a cage37 of the follower 33 and is subject to the pressure of a spring 38.

l The triple valve casing6 also contains the usual quick action valve mechanism comprising aL piston 39,-a brake pipe rvent `valve 40 adapted to bev operated by said piston, and a check valve 41,. controlling communication lfjron the brake pipe 4 to vent valvecham- 6I 2.' i i. i

The retaining valve device 5 may comprise .a casing containing retaining valves 43 and V44, subgectrespectively to the pressures of springs 45 and 46. Ay pipe 47 lconnects eX- haust passage 23 with chamber y48 of the retaining valve device and a cockv49 operable f by ahandle 50 is adapted in one position to connect chamber 48, through port 50 with a passage 51 leading to the retaining valve 44, and in another position to connect said chamber with a chamber52, rhavinga.passage 53, Y i

leading to the retaining valve 43. y

The pressure of spring 17 yis such'that when the normal p'ressurejis carried in the brake system, and'in ftlie auxiliaryreservoir, the

pressure of lthe kspring 17 will besulicient to maintain the diaphragm 13 in the position shown inthe drawing, with the stem `19 main-k tained in its righthand position by spring 28,

so that valve 22 uncovers .passage 23.' The spring 34 is of such force thatit will operate the diaphragm 30V to retractthe pin 35 from thestem 19 when the brake pipe pressure has the normal running pressure, preferably a predetermined degree below that required to effect a full service application of the brakes.

In operation, when the usual normal running pressure is carried in the brake pipe, the

`been reduced a predetermined degree below 90 'v rl`his normal running pressure is not sufficient to overcome the resistance of the spring 17, so that the stem 19 holds the valve 22 in the position shown in the drawing, in which passage 23 is open to the atmospheric exhaust passage 25. TWhen the brakes are released, the brake cylinder 2 is connected through Vpassage 55, and cavity 56 in slide valve 10 with passage 23, so that fluid under 'pressure is vented directly to the* atmosphere, by way of exhaust poit 25. Y

1f it is desired to retain pressure in the brake cylinder when the brakes are released,

Y the engineer adjusts the usual feed valve device (not shown) on the locomotive, so as to provide a definite higher pressurev in the brake pipe Vthan the normalpressure carried in the brake pipe.

" 'When the auxiliary reservoir is charged retainingvalve device.

If the retaining valve cock 49 is set in the position shown in the drawing, fluid from the brake cylinder will ow past the retaining valve 44 and through passages 57 to chamber 52, and thence past the retaining valve 43.

' If the cock 49 is set to another position, Vfluid from the brake cylinder is released past the retaining valve 43 only, and the pressure retained in the brake cylinder then depends on the setting of the retaining valve 43.

lVhen the stem 19 is moved to the left, as above described, the teat on the pin 35 is shifted into the groove 36 and thereby locks the stem 19 in its left handposition.

Y VThe locking of the stem in this positionl prevents movement of the stem toward the right when the auxiliary reservoir pressure is reduced'in diaphragm chamber 14 in `effecting applications of the brakes, even when the brake pipe pressure is reduced to the extent I thatV a full service application of the brakes is effected.

InV order to release the pin 35 from its locking engagement with the stem 19, it is necessary to reduce the brake pipe pressure to a predetermined degree below the normal pressure carried in the brake pipe, preferably to a predetermined degree below that required to effect a full service application of the brakes. When theV brake pipe presure is thus reduced, the spring 34 overcomes thebrake I Y pipe pressure in chamber v31 and the `diaphragm is moved upwardly, so asto lift the pin out of engagement with the groove 36.

The auxiliary reservoir pressure in chamber 14 being correspondingly reduced, the diaphragm 13 is moved to the right by spring 17, so that the stem 19 is returned to its right hand position by spring 28, thus causing the valve 22 to uncover the passage 23.

The brake pipe pressure may now be increased to the normal pressure, the feed valve device having been adjusted to maintain the brake pipe pressure at the normal pressure instead of the higher than normal pressure, and the parts ofthe release controlling valve device will remain inthe positions shown in the drawing.

The frictional resistance of the pin 35 to movement of the stem 19 is limited by-making the pin 35 Vmovable relatively to the dia.- phragm 30 and by employing the relatively light spring 38, Vthrough which spring the pin is pressed into engagement with the stem. Thus the pressure with which the pin 35 presses against the stem 19 is limited to the pressure exerted by the spring 38.

l/Vhile one illustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to that embodiment or otherwise than by the terms of the appended claims. v Y

, Having now described my invention, what is claimed as new and desired to be secured by Letters Patent, is:

1. In a Huid pressure brake, the combina- Vtion with a brake cylinder, brake pipe, and

triple valve device, of a valvefor controlling communication through said triple valve device from the brake cylinder to a direct exhaust port, means operated by an increase in brake pipe pressure above normal for operating said valve to cut off said communication, and means for locking said valve in its cut-o position, said locking means being released upon a predetermined reduction in brake pipe pressure below the normal.

2..In a fluid pressure brake, the combination with a brake cylinder, brake pipe, and triple valveV device, of a valve for controlling communication through said'triple valve device from the brake cylinder to a direct exhaust port, a movable abutment subject to the opposing pressures of a spring and Huid pressure and operated upon an increase in fluid pressure above the normal brake pipe pressure for shifting said valve to close said communication, a locking member for locking said valve in its closed position, and a movable abutment operated upon a predetermined reduction in pressure below the normal brake pipe'pressure for releasing said locking member. Y

3. In al fluid pressure brake, the combination with a brake cylinder, brake pipepand auxiliary reservoir, of a valve for controlling communication from the brake cylinder to a direct exhaust port, a movable abutment subject to auxiliary reservoir pressure and operated upon a predetermlned increase 1n auxiliary reservoirpressure for shifting said valve to close said communication, a looking member for locking said valve in its closing position, and a movable abutment subject to brake pipe pressure and operated upon a predetermined're'duotion in brake pipe pressure for releasing said locking member.

4. In a fluid pressure brake, the combination vWit-l1 a brake cylinder, brake pipe, and

auxiliary reservoir, of a -valve for controlling Communication from the brake cylinder to a direct exhaust port,-a movable abutment subject to auxiliary reservoir pressure and operatedl upon a predetermined increase V.1n

auxiliary reservoir pressure for shifting said valve to close said communication, a stem for operating said valve, a locking member for locking said stem and thereby said valve in its closing position, and a movable abutment subject to brake pipe pressure and operated upon a predetermined reduction in brake pipe Y A pressure below the normal for operating said member to release said stem.

In testimony whereof I have hereunto set my hand, this 6th day of November, 1929.

CLYDE C. FARMER. 

